/**
 * Copyright 2010-present Facebook.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.facebook.widget;

import android.database.CursorIndexOutOfBoundsException;
import com.facebook.model.GraphObject;

import java.util.ArrayList;
import java.util.Collection;

class SimpleGraphObjectCursor<T extends GraphObject> implements GraphObjectCursor<T>
{
  private int pos = -1;
  private boolean closed = false;
  private ArrayList<T> graphObjects = new ArrayList<T>();
  private boolean moreObjectsAvailable = false;
  private boolean fromCache = false;

  SimpleGraphObjectCursor()
  {
  }

  SimpleGraphObjectCursor(SimpleGraphObjectCursor<T> other)
  {
    pos = other.pos;
    closed = other.closed;
    graphObjects = new ArrayList<T>();
    graphObjects.addAll(other.graphObjects);
    fromCache = other.fromCache;

    // We do not copy observers.
  }

  public void addGraphObjects(Collection<T> graphObjects, boolean fromCache)
  {
    this.graphObjects.addAll(graphObjects);
    // We consider this cached if ANY results were from the cache.
    this.fromCache |= fromCache;
  }

  public boolean isFromCache()
  {
    return fromCache;
  }

  public void setFromCache(boolean fromCache)
  {
    this.fromCache = fromCache;
  }

  public boolean areMoreObjectsAvailable()
  {
    return moreObjectsAvailable;
  }

  public void setMoreObjectsAvailable(boolean moreObjectsAvailable)
  {
    this.moreObjectsAvailable = moreObjectsAvailable;
  }

  @Override
  public int getCount()
  {
    return graphObjects.size();
  }

  @Override
  public int getPosition()
  {
    return pos;
  }

  @Override
  public boolean move(int offset)
  {
    return moveToPosition(pos + offset);
  }

  @Override
  public boolean moveToPosition(int position)
  {
    final int count = getCount();
    if (position >= count)
    {
      pos = count;
      return false;
    }

    if (position < 0)
    {
      pos = -1;
      return false;
    }

    pos = position;
    return true;
  }

  @Override
  public boolean moveToFirst()
  {
    return moveToPosition(0);
  }

  @Override
  public boolean moveToLast()
  {
    return moveToPosition(getCount() - 1);
  }

  @Override
  public boolean moveToNext()
  {
    return moveToPosition(pos + 1);
  }

  @Override
  public boolean moveToPrevious()
  {
    return moveToPosition(pos - 1);
  }

  @Override
  public boolean isFirst()
  {
    return (pos == 0) && (getCount() != 0);
  }

  @Override
  public boolean isLast()
  {
    final int count = getCount();
    return (pos == (count - 1)) && (count != 0);
  }

  @Override
  public boolean isBeforeFirst()
  {
    return (getCount() == 0) || (pos == -1);
  }

  @Override
  public boolean isAfterLast()
  {
    final int count = getCount();
    return (count == 0) || (pos == count);
  }

  @Override
  public T getGraphObject()
  {
    if (pos < 0)
    {
      throw new CursorIndexOutOfBoundsException("Before first object.");
    }
    if (pos >= graphObjects.size())
    {
      throw new CursorIndexOutOfBoundsException("After last object.");
    }
    return graphObjects.get(pos);
  }

  @Override
  public void close()
  {
    closed = true;
  }

  @Override
  public boolean isClosed()
  {
    return closed;
  }

}
